1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/bug.h> |
3 | #include <linux/io.h> |
4 | #include <linux/types.h> |
5 | #include <linux/kdebug.h> |
6 | #include <linux/signal.h> |
7 | #include <linux/sched.h> |
8 | #include <linux/sched/debug.h> |
9 | #include <linux/sched/task_stack.h> |
10 | #include <linux/uaccess.h> |
11 | #include <linux/hardirq.h> |
12 | #include <linux/kernel.h> |
13 | #include <linux/kexec.h> |
14 | #include <linux/sched/signal.h> |
15 | |
16 | #include <linux/extable.h> |
17 | #include <linux/module.h> /* print_modules */ |
18 | #include <asm/unwinder.h> |
19 | #include <asm/traps.h> |
20 | |
21 | static DEFINE_SPINLOCK(die_lock); |
22 | |
23 | void __noreturn die(const char *str, struct pt_regs *regs, long err) |
24 | { |
25 | static int die_counter; |
26 | |
27 | oops_enter(); |
28 | |
29 | spin_lock_irq(lock: &die_lock); |
30 | console_verbose(); |
31 | bust_spinlocks(yes: 1); |
32 | |
33 | printk("%s: %04lx [#%d]\n" , str, err & 0xffff, ++die_counter); |
34 | print_modules(); |
35 | show_regs(regs); |
36 | |
37 | printk("Process: %s (pid: %d, stack limit = %p)\n" , current->comm, |
38 | task_pid_nr(current), task_stack_page(current) + 1); |
39 | |
40 | if (!user_mode(regs) || in_interrupt()) |
41 | dump_mem("Stack: " , KERN_DEFAULT, regs->regs[15], |
42 | THREAD_SIZE + (unsigned long)task_stack_page(current)); |
43 | |
44 | notify_die(val: DIE_OOPS, str, regs, err, trap: 255, SIGSEGV); |
45 | |
46 | bust_spinlocks(yes: 0); |
47 | add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); |
48 | spin_unlock_irq(lock: &die_lock); |
49 | oops_exit(); |
50 | |
51 | if (kexec_should_crash(current)) |
52 | crash_kexec(regs); |
53 | |
54 | if (in_interrupt()) |
55 | panic(fmt: "Fatal exception in interrupt" ); |
56 | |
57 | if (panic_on_oops) |
58 | panic(fmt: "Fatal exception" ); |
59 | |
60 | make_task_dead(SIGSEGV); |
61 | } |
62 | |
63 | void die_if_kernel(const char *str, struct pt_regs *regs, long err) |
64 | { |
65 | if (!user_mode(regs)) |
66 | die(str, regs, err); |
67 | } |
68 | |
69 | /* |
70 | * try and fix up kernelspace address errors |
71 | * - userspace errors just cause EFAULT to be returned, resulting in SEGV |
72 | * - kernel/userspace interfaces cause a jump to an appropriate handler |
73 | * - other kernel errors are bad |
74 | */ |
75 | void die_if_no_fixup(const char *str, struct pt_regs *regs, long err) |
76 | { |
77 | if (!user_mode(regs)) { |
78 | const struct exception_table_entry *fixup; |
79 | fixup = search_exception_tables(add: regs->pc); |
80 | if (fixup) { |
81 | regs->pc = fixup->fixup; |
82 | return; |
83 | } |
84 | |
85 | die(str, regs, err); |
86 | } |
87 | } |
88 | |
89 | #ifdef CONFIG_GENERIC_BUG |
90 | static void handle_BUG(struct pt_regs *regs) |
91 | { |
92 | const struct bug_entry *bug; |
93 | unsigned long bugaddr = regs->pc; |
94 | enum bug_trap_type tt; |
95 | |
96 | if (!is_valid_bugaddr(addr: bugaddr)) |
97 | goto invalid; |
98 | |
99 | bug = find_bug(bugaddr); |
100 | |
101 | /* Switch unwinders when unwind_stack() is called */ |
102 | if (bug->flags & BUGFLAG_UNWINDER) |
103 | unwinder_faulted = 1; |
104 | |
105 | tt = report_bug(bug_addr: bugaddr, regs); |
106 | if (tt == BUG_TRAP_TYPE_WARN) { |
107 | regs->pc += instruction_size(bugaddr); |
108 | return; |
109 | } |
110 | |
111 | invalid: |
112 | die(str: "Kernel BUG" , regs, err: TRAPA_BUG_OPCODE & 0xff); |
113 | } |
114 | |
115 | int is_valid_bugaddr(unsigned long addr) |
116 | { |
117 | insn_size_t opcode; |
118 | |
119 | if (addr < PAGE_OFFSET) |
120 | return 0; |
121 | if (get_kernel_nofault(opcode, (insn_size_t *)addr)) |
122 | return 0; |
123 | if (opcode == TRAPA_BUG_OPCODE) |
124 | return 1; |
125 | |
126 | return 0; |
127 | } |
128 | #endif |
129 | |
130 | /* |
131 | * Generic trap handler. |
132 | */ |
133 | BUILD_TRAP_HANDLER(debug) |
134 | { |
135 | TRAP_HANDLER_DECL; |
136 | |
137 | /* Rewind */ |
138 | regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); |
139 | |
140 | if (notify_die(val: DIE_TRAP, str: "debug trap" , regs: regs, err: 0, trap: vec & 0xff, |
141 | SIGTRAP) == NOTIFY_STOP) |
142 | return; |
143 | |
144 | force_sig(SIGTRAP); |
145 | } |
146 | |
147 | /* |
148 | * Special handler for BUG() traps. |
149 | */ |
150 | BUILD_TRAP_HANDLER(bug) |
151 | { |
152 | TRAP_HANDLER_DECL; |
153 | |
154 | /* Rewind */ |
155 | regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); |
156 | |
157 | if (notify_die(val: DIE_TRAP, str: "bug trap" , regs: regs, err: 0, trap: TRAPA_BUG_OPCODE & 0xff, |
158 | SIGTRAP) == NOTIFY_STOP) |
159 | return; |
160 | |
161 | #ifdef CONFIG_GENERIC_BUG |
162 | if (__kernel_text_address(addr: instruction_pointer(regs: regs))) { |
163 | insn_size_t insn = *(insn_size_t *)instruction_pointer(regs); |
164 | if (insn == TRAPA_BUG_OPCODE) |
165 | handle_BUG(regs: regs); |
166 | return; |
167 | } |
168 | #endif |
169 | |
170 | force_sig(SIGTRAP); |
171 | } |
172 | |
173 | #ifdef CONFIG_DYNAMIC_FTRACE |
174 | extern void arch_ftrace_nmi_enter(void); |
175 | extern void arch_ftrace_nmi_exit(void); |
176 | #else |
177 | static inline void arch_ftrace_nmi_enter(void) { } |
178 | static inline void arch_ftrace_nmi_exit(void) { } |
179 | #endif |
180 | |
181 | BUILD_TRAP_HANDLER(nmi) |
182 | { |
183 | TRAP_HANDLER_DECL; |
184 | |
185 | arch_ftrace_nmi_enter(); |
186 | |
187 | nmi_enter(); |
188 | this_cpu_inc(irq_stat.__nmi_count); |
189 | |
190 | switch (notify_die(val: DIE_NMI, str: "NMI" , regs: regs, err: 0, trap: vec & 0xff, SIGINT)) { |
191 | case NOTIFY_OK: |
192 | case NOTIFY_STOP: |
193 | break; |
194 | case NOTIFY_BAD: |
195 | die(str: "Fatal Non-Maskable Interrupt" , regs: regs, SIGINT); |
196 | default: |
197 | printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n" ); |
198 | break; |
199 | } |
200 | |
201 | nmi_exit(); |
202 | |
203 | arch_ftrace_nmi_exit(); |
204 | } |
205 | |